The invention relates to the transmission of an electromagnetic signal.
When an electromagnetic signal is available at a predetermined point it is sometimes necessary to transmit it to another point, particularly for the purposes of analysis or processing.
In order to effect such transmission, the generation of an optical signal at one end of an optical fiber, its modulation by the electromagnetic signal which has to be transmitted, followed by analysis of the modulated optical signal which has passed through the fiber at the other end thereof, in order to determine the characteristics of the electromagnetic signal has been considered.
However, in addition to the fact that such transmission generally requires the use of highly technical components which have a high cost and are susceptible, if not to failures at least to frequent inspection, at both ends of the fiber, it proves very inappropriate for an advantageous, but not restrictive, application of the invention which consists of transmitting an electromagnetic signal from a point which is difficult of access to a maintenance team. In fact, if a component fails, response times may be relatively long and may as a consequence result in a prolonged interruption in transmission which may in some cases be unacceptable.